• 전자공학회논문지B
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• 제33B권8호
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• pp.50-59
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• 1996

In this paper, a new hierarchical motion estiamtion scheme using the wavelet transformed multi-resolution image layers is proposed. Compared with the full search motion estimation method, the existing hierarchical methods remarkably reduce the amount of the computation but their efficiencies are depreciated by the local minima problem. In order to solve the local minima problem, the multi-resolution image layers are composed using the wavelet transform and the number of layers participated in the motion estimation for a block is determined by considering of its low band energy and higher band energy on the first wavelet transformed layer. The ratio between higher band energy and low band energy of each block is evaluated and in the case of the blocks which include relatively large higher band energy, the motion estimation is carried out in the high resolution layer. Otherwise, all layers are used. The final motion vectors are obtained in the first wavelet transformed layer. So less bits for motion vectors are transmitted, and the decomposition of received image using inverse wavelet transform decreases the blocking effect.

• 대한전기학회논문지
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• 제34권5호
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• pp.201-209
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• 1985

This paper describes a method for the state estimation by a modified fast decoupled estimation method and system decomposition. The state values are gained by using the weighted least square estimation method, fast decoupled estimation method, and modified fast decoupled estimation method. The estimated values of each method were compared about effectiveness of state values, respectively. This paper investigated the effects of impedance of well-condition or ill-condition into lines. The characteristics of state estimation were gained through hierarchical state estimation. Each method was applied to three model power systems, and, the results of test for the proposed method are given.

• Journal of the Korean Data and Information Science Society
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• 제17권3호
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• pp.1009-1019
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• 2006

In this paper, we consider the simultaneous estimation problem for the normal means. We set up the model structure using the several different distributions of the errors for observing their effects of model perturbation for the error terms in obtaining the empirical Bayes and hierarchical Bayes estimators. We compare the performance of those estimators under model perturbation based on a simulation study.

• Journal of the Korean Statistical Society
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• 제27권1호
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• pp.1-10
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• 1998

In the problem of estimating a vector of unknown regression coefficients under the sum of squared error losses in a hierarchical linear model, we propose the hierarchical Bayes estimator of a vector of unknown regression coefficients in a hierarchical linear model, and then prove the admissibility of this estimator using Blyth's (196\51) method.

• 방송공학회논문지
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• 제8권2호
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• pp.181-197
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• 2003

대역 분할 부호화(Sub-Band Coding: SBC)방식은 계층적 피라미드(hierarchical pyramid) 구조를 갖고 있어 움직임 예측 시 상위 계층에서는 전체적인 이동특성을 추정하고 하위 계층에서는 국부적인 세부 이동 특성을 추정할 수가 있어 실제 동영상 움직임 보상 성능이 매우 우수하다. 이와 같은 계층적 이동보상피라미드를 이용한 기존의 저대역(low-band) 이동보상 피라미드 방식에는 다음 두 가지 문제점들로 인해 매우 심각한 화질 저하가 발생한다. 첫째는 저대역 이동보상 피라미드의 각 계층에서 양자화기가 포함된 부호화기를 사용할 경우 하위 계층의 재생 영상일수록 상위 계층에서 누적된 양자화 오차(quantization error)들을 그대로 포함하기 때문에 연속된 영상에서의 정확한 이동 보상이 어렵게 된다. 둘째는 피라미드의 계층적 구조 모순으로 상위 계층예서 잘못된 움직임 추정(motion estimation)은 하위 계층으로 진행될수록 막대한 성능 저하의 원인이 된다. 본 논문에서는 우선 대역분할 부호화 방식을 이용한 대역별 계층적 이동보상에 대한 수학적 분석을 하였으며, 이를 바탕으로 제안되었던 통과 대역(pass-band) 이동보상 피라미드 방식이 누적된 양자화 오차 요인이 제거됨으로서 기존의 저대역 이동보상 피라미드에 비해 성능이 우수하다는 것을 이론적으로 분석하여 이를 증명하였다. 또한 계층적 이동보상 피라미드에서 매우 중요한 최고 계층의 초기 이동벡터 추정을 위하여 에지 패턴 분류를 이용한 이동벡터 추정 방식을 새로이 제안하였으며, 실험 결과 성능의 우수함이 입증되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.143-145
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• 2005

In this paper, an empirical study result on pattern estimation method is devoted to reveal underlying data patterns with a relatively reduced computational cost. Presented method performs crisp type clustering with given n number of data samples by means of the sequential agglomerative hierarchical nested model (SAHN). Conventional SAHN based clustering requires large computation time in the initial step of algorithm. To deal with this concern, we modified overall process with a partial approach. In the beginning of this method, we divide given data set to several sub groups with uniform sampling and then each divided sub data group is applied to SAHN based method. The advantage of this method reduces computation time of original process and gives similar results. Proposed is applied to several test data set and simulation result with conceptual analysis is presented.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.21-24
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• 2002

This paper presents a new method for the motion detection of vehicles using hierarchical motion estimation and parallel processing. It captures the road image by using a CMOS sensor. It divides the captured image into small blocks and detects the motion of each block by using a block-matching method which is based on a hierarchical motion estimation and parallel processing for the real-time processing. The parallelism is achieved by using the pipeline and the data flow technique. The proposed method has been implemented with an embedded system. Experimental results show that the proposed method detects the motion of vehicles in real-time.

• 전자공학회논문지B
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• 제30B권6호
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• pp.35-48
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• 1993

In this paper, a hierarchical motion vector estimation algorithm using pyramidal structure is proposed. Using a smaller measurement window at each level of a pyramid than that of the conventional scheme, the proposed algorithm, based on the TSS(three step search), reduces the computational complexity greatly with its performance comparable to that of the TSS. By increasing the number of cnadidate motion vectors which are to be used as the initial search points for motion vector estimation at the next level, the performance improves further. Then the computational complexity of the proposed hierarchical algorithm depends on the number of candidate motion vectors, with its PSNR (peak signal to noise ratio) ranging between those of the TSS and the full search method. The simulation results with two different block sizes and various test sequences are given and its hardware implementation is also sketched.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 Proceedings International Workshop on New Video Media Technology
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• pp.41-44
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• 1996

A new three step hierarchical search algorithm for motion estimation is proposed. The proposed algorithm exploits the motion correlation of spatially neighboring blocks and the motion continuity of temporally neighboring blocks to alleviate the local minimum problem in the first step of the three step hierarchical search algorithm (3SHS). Simulation results show that the proposed scheme achieves significant improvements in both estimation accuracy and performance reliability compared with the existing fast block matching algorithm including 3SHS, while maintaining almost the same computational complexity as 3SHS. The proposed scheme also possesses the regularity and simplicity of hardware-oriented features.

• Communications for Statistical Applications and Methods
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• 제9권2호
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• pp.315-324
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• 2002

For estimating the error variance under the relative squared error loss in two-way analysis of variance models, we provide a class of hierarchical Bayes estimators and then derive a subclass of the hierarchical Bayes estimators, each member of which dominates the best multiple of the error sum of squares which is known to be minimax. We also identify a subclass of non-minimax hierarchical Bayes estimators.